Unverified Commit bbde0152 authored by Palmer Dabbelt's avatar Palmer Dabbelt
Browse files

RISC-V: add support for restartable sequences 

Add support for RSEQ, restartable sequences, for RISC-V.  This also adds
support for the related selftests.

Note: the selftests require a linker with 3e7bd7f2414 ("RISC-V: Fix
linker problems with tls copy relocs."), which was first released in
2.33 (from 2019).

* palmer/riscv-rseq:
  rseq/selftests: Add support for RISC-V
  RISC-V: Add support for restartable sequence
parents 6ae1af9c 6d1a6f46

arch/riscv/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -101,6 +101,7 @@ config RISCV 
	select HAVE_FUNCTION_ARG_ACCESS_API

	select HAVE_STACKPROTECTOR

	select HAVE_SYSCALL_TRACEPOINTS

	select HAVE_RSEQ

	select IRQ_DOMAIN

	select IRQ_FORCED_THREADING

	select MODULES_USE_ELF_RELA if MODULES

arch/riscv/kernel/entry.S

+4 −0
Original line number Diff line number Diff line
@@ -225,6 +225,10 @@ ret_from_syscall: 
	 * (If it was configured with SECCOMP_RET_ERRNO/TRACE)

	 */

ret_from_syscall_rejected:

#ifdef CONFIG_DEBUG_RSEQ

	move a0, sp

	call rseq_syscall

#endif

	/* Trace syscalls, but only if requested by the user. */

	REG_L t0, TASK_TI_FLAGS(tp)

	andi t0, t0, _TIF_SYSCALL_WORK

arch/riscv/kernel/signal.c

+2 −0
Original line number Diff line number Diff line
@@ -258,6 +258,8 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) 
		}

	}



	rseq_signal_deliver(ksig, regs);



	/* Set up the stack frame */

	ret = setup_rt_frame(ksig, oldset, regs);

tools/testing/selftests/rseq/param_test.c

+23 −0
Original line number Diff line number Diff line
@@ -207,6 +207,29 @@ unsigned int yield_mod_cnt, nr_abort; 
	"addiu " INJECT_ASM_REG ", -1\n\t" \

	"bnez " INJECT_ASM_REG ", 222b\n\t" \

	"333:\n\t"

#elif defined(__riscv)



#define RSEQ_INJECT_INPUT \

	, [loop_cnt_1]"m"(loop_cnt[1]) \

	, [loop_cnt_2]"m"(loop_cnt[2]) \

	, [loop_cnt_3]"m"(loop_cnt[3]) \

	, [loop_cnt_4]"m"(loop_cnt[4]) \

	, [loop_cnt_5]"m"(loop_cnt[5]) \

	, [loop_cnt_6]"m"(loop_cnt[6])



#define INJECT_ASM_REG	"t1"



#define RSEQ_INJECT_CLOBBER \

	, INJECT_ASM_REG



#define RSEQ_INJECT_ASM(n)					\

	"lw " INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t"		\

	"beqz " INJECT_ASM_REG ", 333f\n\t"			\

	"222:\n\t"						\

	"addi  " INJECT_ASM_REG "," INJECT_ASM_REG ", -1\n\t"	\

	"bnez " INJECT_ASM_REG ", 222b\n\t"			\

	"333:\n\t"





#else

#error unsupported target

tools/testing/selftests/rseq/rseq-riscv.h

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